31 Oct
2008
31 Oct
'08
9:43 a.m.
-----------Original Message:
Date: Fri, 31 Oct 2008 00:48:21 -0700
From: "Chuck Guzis" <cclist at sydex.com>
Subject: Re: Looking for a ST419
On 30 Oct 2008 at 10:45, Chris Elmquist wrote:
I realize that the operating system had individual
sector write-ability
but was that accomplished by read-modify-write of that individual sector
in a controller buffer and then the entire track rewritten? or did the
controller sync to the beginning of the specific sector and write it
in place?
Just that way--like a floppy--there are address marks and sector
headers that mark the beginning of each sector. At least that's the
way most controllers work. Of course, since the data stream from an
ST412 interface is just a raw bunch of pulses, one could record
anything on a track that one wanted, within the electrical limits of
the drive.
Cheers,
Chuck
----------------Reply:
The Cromemco STDC ST506-type controllers are an example of a controller
that *did* format/read/write entire 10K tracks (no physical sectors), with a
four-track cache.
m